• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.1-9
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• 2012

This study proposed a method to determine the number and location of bus information terminals (BIT), which is a device to provide passengers with bus arrival time at bus stops in a Bus Information System (BIS). In low-density area, it is not efficient to survey bus demands such as the number of passengers at all bus stops due to time and cost. This kind of a survey would, however, competently cover all bus stops if performed inside the bus. The number of riding-on and -off passengers is observed for every bus stop, and this data collection is repeated over all day. Data obtained from the survey are aggregated each bus stop. This study defines Utility Index (UI), an aggregate each bus stop. Bus stops are ranked according to UI and determined for a BIT within budget limitation. As a case study, a bus line in Jeju island, Korea, was dealt with. This case showed that the more aggregate the better data quality. This study is expected to contribute to solving a location problem of BITs in a BIS.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.3
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• pp.1-8
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• 2011

The parking guidance system can increase driver's convenience with detailed parking information service, but it continuously consumes electrical energy with large amount of sensors, displays and control modules. With the increase of the demand for green and sustainable building design, it becomes a meaningful issue for parking guidance system to reduce operating power. This paper presents the preliminary design and estimated results of a parking guidance system which is optimized to reduce the power consumption mainly on detectors and displays. The system design is based on commercial wireless parking detectors, wireless-loop-detector and earth-magnetic-detector. We have performed system architecture design, communication network design, parking information service scenario planning, battery life regulation and at last operating power estimation. With the 7 years of battery replace cycle, the estimated result for power consumption of designed system was 0.33W/slot, which is 13% of the traditional system's estimation result. The estimated annual maintain cost was similar to the traditional ultrasonic sensor based system's. The low power operable designed system can be expected to reduce CO2 emission.

• Journal of Korea Port Economic Association
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• v.23 no.4
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• pp.139-157
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• 2007

The purpose of this paper is to analyze the competitiveness of the logistics industry of three countries - Korea, China and Japan - by looking into their logistics industry structure and the related regulations. For this aim, the paper examined the modal distribution of transportation, transport infrastructure, freight cost structure and regulation in transport sector in these countries. Furthermore, this study suggests some proposals for the further cooperation to bring sustainable progress in the logistics sector across Northeast Asia. The main suggestions of this paper are as follows: First, Korean government needs to strategize its options in the logistics industry, the most competitive in the country’s service sector, in upcoming FTA negotiations with China and Japan. Second, Korea needs to foster Busan into a strategic point for the Rail Ferry System and Road Feeder System. Third, Korea should participate in establishing shuttle flight service in Northeast Asia amid exploding flight demand from active economic interchange and tourism industry development.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.646-651
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• 2018

This paper reports that the electronic properties at a $P3HT/TiO_2$ interface associated with exciton dissociation and transport can be tailored by the insertion of a graphene quantum dot (GQD) layer. For donor/acceptor interface modification in an $ITO/TiO_2/P3HT/Al$ photovoltaic (PV) device, a continuous GQD film was prepared by a sonication treatment in solution that simplifies the conventional processes, including laser fragmentation and hydrothermal treatment, which limits a variety of component layers and involves low cost processing. The high conductivity and favorable energy alignment for exciton dissociation of the GQD layer increased the fill factor and short circuit current. The origin of the improved parameters is discussed in terms of the broad light absorption and enhanced interfacial carrier transport.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.147-156
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• 2018

PURPOSES : The purpose of this study is to analyze the characteristics of the weight values of evaluation items by traffic safety project type. METHODS : In general, a large-scale investment in projects such as the traffic safety project requires economic analyses to be performed in advance. However, there is an argument for considering special characteristics of the traffic safety project. Therefore, this study conducted characteristic analysis of the weight values of evaluation items. The analysis consisted of two steps. The first step was hypothesis verification using analysis of variance (ANOVA). In this process, the authors examined whether the weight of evaluation items is the same regardless of the traffic safety project type. Based on the first step's results, the authors proceeded to the second step. The objective of this step was to analyze how different the weight values are by traffic safety project type using an analytic hierarchy process. RESULTS : According to the ANOVA test results, the benefit to cost ratios have different weight values based on traffic safety project type at the 0.01 significance level. The policy evaluation items, such as the plans connection, resident opinion, and regional equity, also showed the same results except that the result for the related plans connection was statistically significant at the 0.05 level. Based on the first step's result, the AHP analysis in the second step showed that the traffic safety projects for vulnerable users and pedestrians have very low weight values in economic evaluation factors compared with other safety project types. The weight values for vulnerable users and pedestrians were 0.29 and 0.26, respectively, in economic evaluation items. On the other hand, the weight values for other safety project types were around 0.6. Among the policy evaluation items, resident opinion showed a higher weight value than other factors, such as connection and regional equity items. CONCLUSIONS : The social and economic impact of a traffic safety project varies by project type and project characteristics. Although the economic approach is overarching and a reasonable methodology is applied for large-scale projects, it should be noted that the safety issue, especially for transportation of vulnerable uses, requires a non-economical approach. Based on the analysis results, this study suggests that the priority of the projects should be determined by separating them into independent assessment groups depending on their characteristics.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.202-210
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• 2005

In this study, the fly ash was employed as a possible alternative to the bentonite for its high sorption capacity against cationic heavy metal. To consider the constituents of barrier possibly used, the specimens were mixed with different material contents (fly ash : weathered soil : bentonite), then sorption test was performed. Also the specimens were molded on the wet side of optimum moisture contents like mixing ratio of sorption test and their hydraulic conductivities were measured in flexible-wall permeameters. And to confirm the effect of dissolved cations, the hydraulic conductivity tests were repeated by converting the permeant liquids from water to $Cd^{2+}$ solution. Finally, the Cd-concentration at the effluent was analyzed for 500hrs to compare the effectiveness of each specimen in contaminant retardation. Test results showed that the more the ratio of fly ash increase, the more Kd value increase, and the hydraulic conductivity of weathered soil/bentonite (95:5) mixture was the lowest $(2.9*10^{-8}cm/sec)$, and specimens made of fly ash and fly ash/weathered soil mixtures showed similar hydraulic conductivity. Although the permeant liquid was changed from water to $Cd^{2+}$ solution, the hydraulic conductivity of all specimens except for weathered soil maintained similarly like before. Consequently, the initial breakthrough point of Cd in weathered soil specimen was observed at about 5hrs after the test started while that of fly ash specimens was not observed during the whole test period of 500hrs. The results implied that fly ash had a sufficient retardation capacity against contaminant transport possibly by its high sorption capacity although it showed little effect on the reduction of hydraulic conductivity. Based on the test results, it could be concluded that the fly ash can be possibly used as a suitable barrier material in containment system to attenuate the contaminant transport for its high retardation capacity and for the low cost.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.2
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• pp.121-133
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• 2014

If the spent fuels or the high-level radioactive wastes can be disposed of in the depth of 3~5 km and more stable rock formation, it has several advantages. For example, (1)significant fluid flow through basement rock is prevented, in part, by low permeability, poorly connected transport pathways, and (2)overburden self-sealing. (3)Deep fluids also resist vertical movement because they are density stratified and reducing conditions will sharply limit solubility of most dose-critical radionuclides at the depth. Finally, (4) high ionic strengths of deep fluids will prevent colloidal transport. Therefore, as an alternative disposal concept to the deep geological disposal concept(DGD), very deep borehole disposal(DBD) technology is under consideration in number of countries in terms of its outstanding safety and cost effectiveness. In this paper, for the preliminary applicability analyses of the DBD system for the spent fuels or high level wastes, the DBD concepts which have been developed by some countries according to the rapid advance in the development of drilling technology were reviewed. To do this, the general concept of DBD system was checked and the study cases of foreign countries were described and analyzed. These results will be used as an input for the analyses of applicability for DBD in Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.141-147
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• 2010

Liquefied natural gas(LNG) is natural gas that has been converted temporarily to liquid form for ease of storage and transport it. Natural gas is the worlds cleanest burning fossil fuel and it has emerged as the environmentally preferred fuel of choice. In Korea, the demand of this has been increased since the first import from the Indonesia in 1986. LNG takes up about 1/600th the volume of natural gas in the gaseous state by cooling it to approximately $-162^{\circ}C(-260^{\circ}F)$. The reduction in volume therefore makes it much more cost efficient to transport and store it. Modern LNG storage tanks are typically the full containment type, which is a double-wall construction with reinforced concrete outer wall and a high-nickel steel inner tank, with extremely efficient insulation between the walls. The insulation will be installed to LNG outer tank for the isolation of cryogenic temperature. The insulation will be installed in the base slab, wall and at the roof. According to the insulation's arrangement, the different aspects of temperature transmission is shown around the outer tank. As the result of the thermal & stress analysis, by the installing cellular glass underneath the perlite concrete, the temperature difference is greatly reduced between the ambient temperature and inside of concrete wall, also reducing section force according to temperature load.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.582-589
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• 2010

As a part of the back-end fuel cycle, transportation of spent nuclear fuel (SNF) from nuclear power plants (NPPs) to a fuel storage facility is very important in establishing a nuclear fuel cycle. In Korea, the accumulated amount of SNF in the NPP pools is troublesome since the temporary storage facilities at these NPP pools are expected to be full of SNF within ten years. Therefore, Korea cannot help but plan for the construction of an interim storage facility to solve this problem in the near future. Especially, a decision on several factors, such as where the interim storage facility should be located, how many casks a transport ship can carry at a time and how many casks are initially required, affect the configuration of the transportation system. In order to analyze the various possible candidate scenarios, we assumed four cases for the interim storage facility location, three cases for the load capacity that a transport ship can carry and two cases for the total amount of casks used for transportation. First, this study considered the currently accumulated amount of SNF in Korea, and the amount of SNF generated from NPPs until all NPPs are shut down. Then, how much SNF per year must be transported from the NPPs to an interim storage facility was calculated during an assumed transportation period. Second, 24 candidate transportation scenarios were constructed by a combination of the decision factors. To construct viable yearly transportation schedules for the selected 24 scenarios, we created a spreadsheet program named TranScenario, which was developed by using MS EXCEL. TranScenario can help schedulers input shipping routes and allocate transportation casks. Also, TranScenario provides information on the cask distribution in the NPPs and in the interim storage facility automatically, by displaying it in real time according to the shipping routes, cask types and cask numbers that the user generates. Once a yearly transportation schedule is established, TranScenario provides some statistical information, such as the voyage time, the availability of the interim storage facility, the number of transported casks sent from the NPPs, and the number of transported casks received at the interim storage facility. By using this information, users can verify and validate a yearly transportation schedule. In this way, the 24 candidate scenarios could be constructed easily. Finally, these 24 scenarios were compared in terms of their operation cost.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.22-32
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• 2002

This paper describes about non-burial AVI (Automatic Vehicle Identification) system using general vehicle as probe car for obtaining more accurate traffic information while conserving road pavement surface. Existing spot traffic detectors have their own limits of not obtaining right information owing to its mathematical method. Burial AVI systems have some defects, causing traffic jam, needing much maintenance cost because of frequent cutting of loop and piezo-electric sensors. Especially, they have hard time to make right detection, when it comes to jamming time. Therefore, in this paper, we propose non-burial AVI system with laser trigger unit. Proposed non-burial AVI system is developed to obtain regional traffic information from normal Passing vehicle by automatic license number recognition technology. We have adapted it to national highway section between Suwon city and Pyong$\~$Taek city(9.5km) and get affirmative results. Vehicle detection rate of laser trigger unit is more than 95$\%$, vehicle recognition rate is 87.8$\%$ and vehicle matching rate is about 14.3$\%$. So we regard these as satisfying results to use the system for traffic information service. We evaluate proposed AVI system by regulation of some institutions which are using similar AVI system and the proposed system satisfies all conditions. For future study, we have plan of detailed research about proper lane number from all of the target lanes, optimal section length, information service period, and data fusion method for existing spot detector.